/*
     This file is part of GNUnet.
     Copyright (C) 2012 GNUnet e.V.

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
*/

/**
 * @file util/gnunet-config.c
 * @brief tool to access and manipulate GNUnet configuration files
 * @author Christian Grothoff
 */
#include "platform.h"
#include "gnunet_util_lib.h"


/**
 * Name of the section
 */
static char *section;

/**
 * Name of the option
 */
static char *option;

/**
 * Value to set
 */
static char *value;

/**
 * Treat option as a filename.
 */
static int is_filename;

/**
 * Whether to show the sections.
 */
static int list_sections;

/**
 * Return value from 'main'.
 */
static int ret;

/**
 * Should we generate a configuration file that is clean and
 * only contains the deltas to the defaults?
 */
static int rewrite;

/**
 * Print each option in a given section.
 *
 * @param cls closure
 * @param section name of the section
 * @param option name of the option
 * @param value value of the option
 */
static void
print_option (void *cls, const char *section,
	      const char *option,
	      const char *value)
{
  fprintf (stdout,
	   "%s = %s\n", option, value);
}


/**
 * Print out given section name.
 *
 * @param cls unused
 * @param section a section in the configuration file
 */
static void
print_section_name (void *cls,
                    const char *section)
{
  fprintf (stdout, "%s\n", section);
}


/**
 * Main function that will be run by the scheduler.
 *
 * @param cls closure
 * @param args remaining command-line arguments
 * @param cfgfile name of the configuration file used (for saving, can be NULL!)
 * @param cfg configuration
 */
static void
run (void *cls,
     char *const *args,
     const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  struct GNUNET_CONFIGURATION_Handle *out = NULL;
  struct GNUNET_CONFIGURATION_Handle *diff = NULL;

  if (rewrite)
  {
    struct GNUNET_CONFIGURATION_Handle *def;

    def = GNUNET_CONFIGURATION_create ();
    if (GNUNET_OK !=
        GNUNET_CONFIGURATION_load (def, NULL))
    {
      fprintf (stderr,
               _("failed to load configuration defaults"));
      ret = 1;
      return;
    }
    diff = GNUNET_CONFIGURATION_get_diff (def,
                                          cfg);
    cfg = diff;
  }
  if ( ((! rewrite) && (NULL == section)) || list_sections)
  {
    if (! list_sections)
    {
      fprintf (stderr,
               _("--section argument is required\n"));
    }
    fprintf (stderr,
             _("The following sections are available:\n"));
    GNUNET_CONFIGURATION_iterate_sections (cfg,
                                           &print_section_name,
                                           NULL);
    ret = 1;
    goto cleanup;
  }

  if ( (NULL != section) && (NULL == value) )
  {
    if (NULL == option)
    {
      GNUNET_CONFIGURATION_iterate_section_values (cfg,
                                                   section,
						   &print_option,
                                                   NULL);
    }
    else
    {
      if (is_filename)
      {
	if (GNUNET_OK !=
	    GNUNET_CONFIGURATION_get_value_filename (cfg,
                                                     section,
                                                     option,
                                                     &value))
	{
	  GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
				     section, option);
	  ret = 3;
          goto cleanup;
	}
      }
      else
      {
	if (GNUNET_OK !=
	    GNUNET_CONFIGURATION_get_value_string (cfg, section, option, &value))
	{
	  GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
				     section, option);
	  ret = 3;
          goto cleanup;
	}
      }
      fprintf (stdout, "%s\n", value);
    }
  }
  else if (NULL != section)
  {
    if (NULL == option)
    {
      fprintf (stderr, _("--option argument required to set value\n"));
      ret = 1;
      goto cleanup;
    }
    out = GNUNET_CONFIGURATION_dup (cfg);
    GNUNET_CONFIGURATION_set_value_string (out,
                                           section,
                                           option,
                                           value);
  }
  if ( (NULL != diff) || (NULL != out) )
  {
    if (GNUNET_OK !=
	GNUNET_CONFIGURATION_write ((NULL == out) ? diff : out,
                                    cfgfile))
      ret = 2;
  }
  if (NULL != out)
    GNUNET_CONFIGURATION_destroy (out);
 cleanup:
  if (NULL != diff)
    GNUNET_CONFIGURATION_destroy (diff);
}


/**
 * Program to manipulate configuration files.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc, char *const *argv)
{
  struct GNUNET_GETOPT_CommandLineOption options[] = {
    GNUNET_GETOPT_option_flag ('f',
                                  "filename",
                                  gettext_noop ("obtain option of value as a filename (with $-expansion)"),
                                  &is_filename),
    GNUNET_GETOPT_option_string ('s',
                                     "section",
                                     "SECTION",
                                     gettext_noop ("name of the section to access"),
                                     &section),
    GNUNET_GETOPT_option_string ('o',
                                     "option",
                                     "OPTION",
                                     gettext_noop ("name of the option to access"),
                                     &option),
    GNUNET_GETOPT_option_string ('V',
                                     "value",
                                     "VALUE",
                                     gettext_noop ("value to set"),
                                     &value),
    GNUNET_GETOPT_option_flag ('S',
                                  "list-sections",
                                  gettext_noop ("print available configuration sections"),
                                  &list_sections),
    GNUNET_GETOPT_option_flag ('w',
                                  "rewrite",
                                  gettext_noop ("write configuration file that only contains delta to defaults"),
                                  &rewrite),
    GNUNET_GETOPT_OPTION_END
  };
  if (GNUNET_OK !=
      GNUNET_STRINGS_get_utf8_args (argc, argv,
                                    &argc, &argv))
    return 2;

  ret = (GNUNET_OK ==
	 GNUNET_PROGRAM_run (argc,
                             argv,
                             "gnunet-config [OPTIONS]",
			     gettext_noop ("Manipulate GNUnet configuration files"),
			     options,
                             &run, NULL)) ? 0 : ret;
  GNUNET_free ((void*) argv);
  return ret;
}

/* end of gnunet-config.c */
